Electrical connectors, for example those used in connection with differential signaling, twisted pair wiring, have a variety of different formats. For example, an RJ-11 electrical connector can have either two or three pairs of wires, or either four or six total wires. An RJ-45 electrical connector typically has four pairs of wires, representing eight total wires. Other types of electrical connectors have differing numbers of wires as well.
In some cases, the physical characteristics of a particular electrical connector allow that connector to be compatible with electrical connectors of alternative formats. For example, RJ-11 plugs having four wires are often constructed to fit in the same housing as an RJ-11 plug having six wires; accordingly, both variants can fit into the same RJ-11 jack. Similarly, RJ-45 jacks generally have a greater width than RJ-11 jacks, but are otherwise similarly sized. As such, RJ-45 jacks can receive an RJ-11 plug, when such a plug is either intentionally, or sometimes unintentionally, inserted.
The size similarities and physical compatibility of electrical connectors of various types can, at times, lead to drawbacks. For example, although a plug can be inserted into a mismatched (yet physically compatible) jack in some circumstances, the contacts of the plug may not directly correspond to or align with the contacts of the mismatched jack. For example, an RJ-11 plug can be inserted into the physical opening of an RJ-45 jack, but because of the different number and arrangement of wire pairs, contacts of the RJ-11 plug will not align with at least the two outermost contact springs of the RJ-45 jack (typically designated as pins 1 and 8). This misalignment of wires can lead to undue stress on the electrical connector. For example, in the event of insertion of an RJ-11 plug into an RJ-45 jack, it is often the case that a plastic housing portion of the RJ-11 plug engages the outermost contact springs of an RJ-45 jack, causing them to deform much more than would otherwise occur when those contact springs engage wires of a plug.
This insertion of a physically similar plug does not necessarily harm the RJ-45 jack during an initial insertion of that RJ-11 plug. However, RJ-45 jacks (and other such connectors) are designed to have a finite life span, typically referred to as a minimum number of insertions of a plug into the jack before the resiliency of the contact springs of the jack may become unreliable. When an RJ-11 plug is inserted, the increased deformation of contact springs in the RJ-45 jack results in decreased lifespan of the jack, due to loss of resiliency of the outermost contact springs.
To ensure that RJ-45 jacks have adequate life, the contact springs of the RJ-45 jack can be manufactured from a beryllium-copper material, which has good resiliency even when deflected a relatively large distance. However, this material can be expensive, difficult to obtain, and environmentally hazardous when disposed of.
For these and other reasons, improvements are desirable.